Now that MOSS is built and installed, you will need to go back and build the rest of GCC (in particular, libgcc, which couldn't be built above). It should succeed now that all the needed libc header files are available in the installation directories.
$ cd ../gcc-2.7.2 $ make install LANGUAGES=c
Now you should be ready to cross-compile real programs for use with MOSS. Just use i386-moss-gcc as you would use a native gcc.